Heretofore, it has been known to install a tape feeder in a mounter for mounting electronic components onto a board, as a component supply device for supplying the electronic components to the mounter.
Typically, this type of tape feeder is equipped with a reel wound with a tape which holds electronic components at certain intervals, and adapted to feed the tape pulled out from the reel, to a pickup position where each of the electronic components is suckingly held by a transfer head of the mounter.
The tape which holds the electronic components is provided with feed holes at a given pitch, and a sprocket equipped in the tape feeder is drivenly rotated intermittently by a given feed amount, while bringing a plurality of pins provided on the sprocket into engagement with the feed holes of the tape, whereby the electronic components held by the tape sequentially reach the pickup position.
In the above tape feeder, a situation has arisen where even if the sprocket is rotated by a given feed amount, an actual moving amount is liable to vary due to a production error in individual tape feeders, etc., to cause an inability to accurately feed each of the electronic components to the pickup position.
Therefore, there has been proposed a technique of, in advance of an actual mounting operation, recognizing a position of a sprocket or a tape just after being fed by a given feed amount to derive a deviation relative to a true position, as an offset amount, and, during the mounting operation, performing a feed operation while correctively adding/subtracting the offset amount to/from the given feed amount, to feed each component to an estimated true position derived by the calculation, as disclosed, for example, in JP 2003-124686A (paragraphs [0025] and [0026]) and JP 2003-124687A (paragraphs [0029] and [0030]).
However, the technique disclosed in the above documents is intended to feed each component to an estimated true position derived by correcting a deviation relative to the given feed amount, i.e., derived absolutely by calculation, and thereby the estimated true position is likely to deviate from a proper true position. Thus, there has remained a need for improvement in view of achieving an accurate pickup operation.